Year	% of total electricity output
1990	18.178275895004646
1991	17.598669877551377
1992	17.018019498374347
1993	17.430835428264157
1994	16.76851221173495
1995	17.62531258345671
1996	18.567481036514298
1997	17.915974896087235
1998	16.141061762440728
1999	15.843407326931398
2000	15.054929919232892
2001	13.607140389765615
2002	15.300739963540902
2003	15.237612368954464
2004	14.921960353888679
2005	15.115868049553384
2006	15.499542164741236
2007	14.936536700911542
2008	15.642387586293887
2009	16.96674367560173
2010	16.289887502526103
2011	18.590559054827796
2012	18.61499715041654
2013	19.399971763244395
2014	19.527802953920215
2015	19.947459398051617